Re: [PATCH] libfsimage: add ext4 support for CentOS 5.x

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2012-09-05 at 13:03 +0100, Roger Pau Monne wrote:
> CentOS 5.x forked e2fs ext4 support into a different package called
> e4fs, and so headers and library names changed from ext2fs to ext4fs.
> Check if ext4fs/ext2fs.h and -lext4fs work, and use that instead of
> ext2fs to build libfsimage. This patch assumes that if the ext4fs
> library is present it should always be used instead of ext2fs.
> 
> This patch includes a rework of the ext2fs check, a new ext4fs check
> and a minor modification in libfsimage to use the correct library.
> 
> Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>

Thanks.

Any patch which is intended for 4.2 at this stage needs to come with
some rationale as to why it is acceptable at this late stage.

Therefore unless someone can argue convincingly for it this is 4.3
material.

Ian.

> ---
> Please re-run autogen.sh after applying
> ---
>  config/Tools.mk.in                       |    2 +-
>  tools/config.h.in                        |    3 +++
>  tools/configure.ac                       |    4 ++--
>  tools/libfsimage/Makefile                |    2 +-
>  tools/libfsimage/ext2fs-lib/Makefile     |    5 ++++-
>  tools/libfsimage/ext2fs-lib/ext2fs-lib.c |    5 ++++-
>  tools/m4/extfs.m4                        |   20 ++++++++++++++++++++
>  7 files changed, 35 insertions(+), 6 deletions(-)
>  create mode 100644 tools/m4/extfs.m4
> 
> diff --git a/config/Tools.mk.in b/config/Tools.mk.in
> index 8a52bcc..0859b36 100644
> --- a/config/Tools.mk.in
> +++ b/config/Tools.mk.in
> @@ -56,5 +56,5 @@ CONFIG_SYSTEM_LIBAIO:= @system_aio@
>  ZLIB                := @zlib@
>  CONFIG_LIBICONV     := @libiconv@
>  CONFIG_GCRYPT       := @libgcrypt@
> -CONFIG_EXT2FS       := @libext2fs@
> +EXTFS_LIBS          := @EXTFS_LIBS@
>  CURSES_LIBS         := @CURSES_LIBS@
> diff --git a/tools/config.h.in b/tools/config.h.in
> index bc1ed10..ab726f6 100644
> --- a/tools/config.h.in
> +++ b/tools/config.h.in
> @@ -45,6 +45,9 @@
>  /* libutil header file name */
>  #undef INCLUDE_LIBUTIL_H
>  
> +/* e2fs/e4fs header file name */
> +#undef INCLUDE_EXTFS_H
> +
>  /* Define to the address where bug reports for this package should be sent. */
>  #undef PACKAGE_BUGREPORT
>  
> diff --git a/tools/configure.ac b/tools/configure.ac
> index bb497cc..938bc8b 100644
> --- a/tools/configure.ac
> +++ b/tools/configure.ac
> @@ -35,6 +35,7 @@ m4_include([m4/pkg.m4])
>  m4_include([m4/curses.m4])
>  m4_include([m4/pthread.m4])
>  m4_include([m4/ptyfuncs.m4])
> +m4_include([m4/extfs.m4])
>  
>  # Enable/disable options
>  AX_ARG_DEFAULT_DISABLE([githttp], [Download GIT repositories via HTTP])
> @@ -138,8 +139,7 @@ AC_SUBST(zlib)
>  AC_CHECK_LIB([aio], [io_setup], [system_aio="y"], [system_aio="n"])
>  AC_SUBST(system_aio)
>  AC_CHECK_LIB([crypto], [MD5], [], [AC_MSG_ERROR([Could not find libcrypto])])
> -AC_CHECK_LIB([ext2fs], [ext2fs_open2], [libext2fs="y"], [libext2fs="n"])
> -AC_SUBST(libext2fs)
> +AX_CHECK_EXTFS
>  AC_CHECK_LIB([gcrypt], [gcry_md_hash_buffer], [libgcrypt="y"], [libgcrypt="n"])
>  AC_SUBST(libgcrypt)
>  AX_CHECK_PTHREAD
> diff --git a/tools/libfsimage/Makefile b/tools/libfsimage/Makefile
> index 5a506f3..69fd18a 100644
> --- a/tools/libfsimage/Makefile
> +++ b/tools/libfsimage/Makefile
> @@ -3,7 +3,7 @@ include $(XEN_ROOT)/tools/Rules.mk
>  
>  SUBDIRS-y = common ufs reiserfs iso9660 fat zfs
>  SUBDIRS-$(CONFIG_X86) += xfs
> -ifeq ($(CONFIG_EXT2FS), y)
> +ifneq ($(EXTFS_LIBS), )
>      SUBDIRS-y += ext2fs-lib
>  else
>      SUBDIRS-y += ext2fs
> diff --git a/tools/libfsimage/ext2fs-lib/Makefile b/tools/libfsimage/ext2fs-lib/Makefile
> index 142207f..671fbff 100644
> --- a/tools/libfsimage/ext2fs-lib/Makefile
> +++ b/tools/libfsimage/ext2fs-lib/Makefile
> @@ -4,7 +4,10 @@ LIB_SRCS-y = ext2fs-lib.c
>  
>  FS = ext2fs-lib
>  
> -FS_LIBDEPS = -lext2fs
> +FS_LIBDEPS = $(EXTFS_LIBS)
> +
> +# Include configure output (config.h) to headers search path
> +CFLAGS += -I$(XEN_ROOT)/tools
>  
>  .PHONY: all
>  all: fs-all
> diff --git a/tools/libfsimage/ext2fs-lib/ext2fs-lib.c b/tools/libfsimage/ext2fs-lib/ext2fs-lib.c
> index 36a27dc..ed47146 100644
> --- a/tools/libfsimage/ext2fs-lib/ext2fs-lib.c
> +++ b/tools/libfsimage/ext2fs-lib/ext2fs-lib.c
> @@ -21,8 +21,11 @@
>   * Use is subject to license terms.
>   */
>  
> +/* Include output from configure */
> +#include <config.h>
> +
>  #include <fsimage_plugin.h>
> -#include <ext2fs/ext2fs.h>
> +#include INCLUDE_EXTFS_H
>  #include <errno.h>
>  #include <inttypes.h>
>  
> diff --git a/tools/m4/extfs.m4 b/tools/m4/extfs.m4
> new file mode 100644
> index 0000000..7309da9
> --- /dev/null
> +++ b/tools/m4/extfs.m4
> @@ -0,0 +1,20 @@
> +AC_DEFUN([AX_CHECK_EXTFS], [
> +AC_CHECK_HEADER([ext2fs/ext2fs.h], [
> +AC_CHECK_LIB([ext2fs], [ext2fs_open2], [
> +    AC_DEFINE([INCLUDE_EXTFS_H], [<ext2fs/ext2fs.h>],
> +              [Define extfs header to use])
> +    EXTFS_LIBS="-lext2fs"
> +])
> +])
> +dnl This is a temporary hack for CentOS 5.x, which split the ext4 support
> +dnl of ext2fs in a different package. Once CentOS 5.x is no longer supported
> +dnl we can remove this.
> +AC_CHECK_HEADER([ext4fs/ext2fs.h], [
> +AC_CHECK_LIB([ext4fs], [ext2fs_open2], [
> +    AC_DEFINE([INCLUDE_EXTFS_H], [<ext4fs/ext2fs.h>],
> +              [Define extfs header to use])
> +    EXTFS_LIBS="-lext4fs"
> +])
> +])
> +AC_SUBST(EXTFS_LIBS)
> +])